Hitherto, high-intensity sweeteners have been widely used to impart sweetness to foods, beverages, medicines and quasi drugs, as well as to adjust the taste thereof. In particular, due to the recent rise in health concerns, non- or low-calorie high-intensity sweeteners, and high-intensity sweeteners with low caries-producing effects are widely utilized.
Examples of high-intensity sweeteners include synthetic sweeteners such as aspartame, sucralose, neotame, acesulfame potassium, and the like; and natural sweeteners such as stevia extract, siraitia grosvenori extract, thaumatin, and the like. Of these, natural sweeteners such as stevia extract have become favored as a result of the recent trend toward natural products.
Natural sweeteners, however, exhibit a sweetness quality different from that of sucrose, exhibit a rough taste in their sweetness, and leaves a lingering sweetness (a remaining aftertaste) in the mouth. In addition to the above, stevia extract, in particular, has drawbacks such as a characteristic bitterness and a lack of sweetness due to its slow sweetness expression in the oral cavity.
The term “sweetness quality” used herein refers to the quality of the sweetness itself. In view of an overall evaluation of sweetness, considering its richness, body, fullness, and low distinctiveness, a quality that is closer to that of sucrose is regarded as being better quality. The term “rough taste” used herein refers to a bitter, astringent, sour, stimulating taste, and the like, other than sweetness.
A number of proposals have been made to overcome the above drawbacks inherent in high-intensity sweeteners such as stevia extract.
For example, it has been proposed to use, as an agent for improving the taste of a high-intensity sweetener, nigerooligosaccharide (Patent Document 1), cellooligosaccharide (Patent Document 2), a solvent extract of roasted coffee (Patent Document 3), and the like. Further, as a taste improving agent, which improves the long-lasting aftertaste of aspartame, the use of sodium chloride (Patent Document 4), the combined use of potassium aluminum sulfate and naringin (Patent Document 5), and the like, have been proposed.
Methods involving the use of a sweet flavor (a sucrose flavor) such as maltol to improve the sweetness quality of a high-intensity sweetener have also been proposed. Sucrose flavors are prepared by using an aromatic component having a granulated-sugar-like aroma, such as maltol, ethyl maltol or the like, as a main component, together with a minor constituent such as sucrose lactone, cyclotene, or the like, which is associated with brown sugar and maple syrup; and a natural starting material such as molasses extract, honey extract, and the like (Non-Patent Document 1).
For example, Patent Document 6 suggests using a sweet flavor such as maltol or furaneol, in addition to a high-intensity sweetener such as acesulfame potassium or sucralose, in order to improve the watery taste of sugarless candies that are composed mainly of sugar alcohol. Patent Document 7 teaches a feed additive for livestock comprising a mixture of a stevia extract and a flavoring agent containing a sweet flavor such as maltol or furaneol. Patent Document 7 further teaches that the addition of the feed additive to feed for livestock, including cattle and swine, can make the feed more palatable, and mitigate diarrhea in livestock. None of the above documents, however, discloses or suggests a method for accelerating the sweetness expression of stevia extract. These documents even fail to disclose that stevia extract suffers from slow sweetness expression.
Patent Document 8 teaches that a sweet flavor such as maltol is effective for improving the sweetness quality of aspartame (by expressing fullness and body. However, Patent Document 8 discloses in Example 1 that the sweet flavor is effective only for aspartame, and has no effect on other high-intensity sweeteners such as stevia extract, acesulfame potassium, and the like.
Methods for improving the sweetness quality of a high-intensity sweetener that involve the combined use of several sweeteners have also been proposed. Patent Document 9, for example, discloses using at least one sweetener selected from siraitia grosvenorii extract, stevia extract, licorice extract, and amacha extract, in combination with a syrup containing erythritol and siraitia grosvenorii glycoside in order to improve its sweetness quality. Patent Document 10 teaches that the further addition of stevia and citric acid to guava tea extract and siraitia grosvenorii extract can be used to prepare a healthy tea having a refreshing sweetness and sweet-sour taste. However, Patent Documents 9 and 10 only disclose using siraitia grosvenorii extract (or siraitia grosvenorii glycoside) in an amount equal to or more than the amount of stevia extract, and neither of these documents discloses or suggests using rebaudioside A, which is a main sweetness component of stevia extract, and mogroside V, which is a main sweetness component of siraitia grosvenorii extract, at a specific weight ratio, in order to improve the sweetness quality.
Thaumatin itself can be used as a sweetener. However, because thaumatin exhibits a flavor-enhancing effect and a bitterness-masking effect, it is regarded as a high-intensity sweetener that can also be used as a flavor enhancer, for example. As a method for improving taste quality using thaumatin, Patent Document 11 discloses a method for preparing a dressing, etc., having natural sweetness and good flavor, by using, in addition to thaumatin, at least one member selected from stevia extract, licorice extract, siraitia grosvenorii extract, amacha extract, and the like. Patent Document 12 teaches a method for producing a sweetness composition comprising thaumatin together with at least one member selected from licorice extract, stevia extract, and siraitia grosvenorii extract. However, Patent Documents 11 and 12 nowhere mention combining thaumatin with rebaudioside A, which is a main sweetness component of stevia extract, and mogroside V, which is a main sweetness component of siraitia grosvenorii extract.
Patent Document 1: Japanese Unexamined Patent Publication No. H10-234331
Patent Document 2: Japanese Unexamined Patent Publication No. 2002-223721
Patent Document 3: Japanese Unexamined Patent Publication No. 2006-81544
Patent Document 4: Japanese Unexamined Patent Publication No. S61-212257
Patent Document 5: Japanese Unexamined Patent Publication No. S52-90667
Patent Document 6: Japanese Unexamined Patent Publication No. 2006-340650
Patent Document 7: Japanese Unexamined Patent Publication No. 2001-95502
Patent Document 8: Japanese Unexamined Patent Publication No. H2-276553
Patent Document 9: Japanese Unexamined Patent Publication No. H11-46701
Patent Document 10: Japanese Unexamined Patent Publication No. 2003-274911
Patent Document 11: Japanese. Unexamined Patent Publication No. 2000-166506
Patent Document 12: Japanese Unexamined Patent Publication Application No. S53-104771
Non-Patent Document 1: Saishin Koryo no Jiten (New Encyclopedia of Flavors) (Asakura Publishing Co., Ltd.), pp. 535-537, May 10, 2000, first edition